A solid-state drive/solid-state disk (SSD) is a solid-state storage device that uses integrated circuit (IC) assemblies as memory to persistently store data. SSD technology typically utilizes electronic interfaces that are compatible with traditional block input/output (I/O) hard disk drives (HDDs), thereby providing easy replacement in many common applications.
Write amplification describes an issue corresponding to some forms of non-volatile memory, such as NAND flash memory, which are used in solid state drives (SSDs). Write amplification may be described as a ratio of a number of writes committed to non-volatile memory at an SSD to a number of writes coming from a host computing platform. Write amplification may cause issues for random writes to SSDs. For example, high write amplification may reduce write performance for the SSD, and may increase wear on non-volatile memory cells, thereby degrading endurance of the memory device.
A concept referred to as “multi-stream SSD” provides operating systems and applications with interfaces that separately store data with different attributes. These individual data stores are referred to as “streams.” Streams may be used to indicate when different data writes are associated with one another or have a similar lifetime. That is, a group of individual data writes may be a part of a collective stream, and each stream is identified by a stream ID that is assigned by the operating system or a corresponding application. Accordingly, different data having similar characteristics, or attributes, can be assigned a unique stream ID such that data corresponding to that stream ID can be written to a same block in the SSD.
That is, multi-streaming flash drives enable more flexibility by placing write operations that are related to each other together on the SSDs, thereby both reducing write amplification and increasing the performance of SSDs. For example, efficient stream assignment in multi-streaming flash drives can reduce write amplification, and can improve both the lifetime and the endurance of SSDs.
Currently, stream assignment generally occurs at the application layer by modifying the application performing the data writes, which may not be suitable for systems with multiple instances of different applications due to resultant high maintenance overhead. Moreover, if multiple applications are supported by multiple storage devices at the backend, then the associated overhead will be further increased.
Additionally, in most of the current multi-streaming systems, only a small number of attributes are used for automatic stream detection (i.e., the attributes of frequency and temporal locality of access of a particular entity), thereby limiting an analytical method for detecting streams.